Used vegetable oil builds up day by day in every home. In Spain, two-thirds of this oil ends up in the sewage pipes, making the treatment of sewage water more expensive and complicated. On reaching the purifying plants, the oil affects the smooth running of the air deposits. Also, when the remaining oil ends up in rivers, it forms a superficial layer that prevents the normal exchange of oxygen and alters the ecosytem.

In addition to being an environmental aggression, pouring oil down the sink is a waste. This is something that is already known to our grandmothers who have been making soap for years by mixing used kitchen oil with caustic soda. Nowadays, most Spaniards have replaced home-made soap with pleasant-smelling bath gel, state-of-the-art detergents and a whole range of household cleaning products. However, the chemical, cosmetic and pharmaceutical industries continue making a living on the byproducts of the oil we use to fry prawns and croquettes. In this way, they produce not only soap, cream and detergent, but also wax, candles, paint, varnish, lubricants and even fertilizer.

In September, the first kitchen oil recycling plant in Spain opened in Montmel� (Barcelona). The plant aims to recycle the oil into biodiesel, an ecological fuel that can be used in diesel-powered cars. In June 2003 the first plant to use 100% Spanish technology is due to open in Alcal� de Henares (Madrid). The fuel produced by this plant will power the city's fleet of buses. What's more, glycerine and a small quantity of fertilizer will be produced as a byproduct.

In the next few years more biodiesel plants will be set up: one built by Bionet Europa in Reus (Tarragona), one built by Rograsa in M�rida (Badajoz), one built by EHN in Caparroso (Navarra), one built by Bionorte in Asturias, two built by Naturdiesel and Bionor in the Basque Country� And there are bound to be many more. Because converting a contaminating residue into an ecological and renewable fuel is clearly a highly attractive idea.

But to recycle this used oil you must first collect it. Collection services have been up and running in Spain's major cities for some time, visiting restaurants, colleges and hospitals. The companies charged with collecting the oil hand over 50-60 litre containers which, once filled, are collected free of charge.

But, in the domestic sector, there is still much to do. In some cities, a lorry collects the used oil in predetermined locations on certain days. Other municipalities have permanent containers located in markets and large shopping malls. And all recycling points allow you to deposit this residue.

Also, many private initiatives have been put into practice, such as one started by the University of Granada that hands over the oil to two charities, Madre Coraje and Aval�n. The first produces soap to send to Peru, where it carries out important work in favour of the development of poor communities. Aval�n, on the other hand,� donates the money it makes selling this used oil to recycling companies to AIDS patients.

If your municipality does not have any of these collecting points (call your town hall for more information), try to throw away the oil by wrapping it in a cone-shaped newspaper or in a glass jar so that it ends up in a controlled dump. In this way, you will at least avoid contaminating the water.

Did you know�?
- A single litre of kichen oil contaminates 1,000 litres of water.
- Until little over a year ago, old vegetable oil was also used to make animal feed, but the crisis caused by chicken dioxine contamination in Belgium led to the banning of this practice.

- The National Urban Waste Plan 2000-2006 has as one of its priorities recycling 50% of used vegetable oil in 2002 and 80% by 31 December 2006.

- M�rida was the first Spanish city to distribute giant oil recycling containers among its inhabitants. Thanks to this system, around 60% of used kitchen oil is collected, some 140 tons a year.

- According to a study of the Public Company for Energy Development of Anadalusia (Sodean), biodiesel emits 10% less carbon dioxide than petrol, 40% less exhaust and 98% less sulphur dioxide.

- Biofuels account for 0.5% of all fuels used in the EU. The EU wants to see this increased to 2% in 2005 and 5.75% in 2010.

- In 2004, when the Alcal� de Henares plant is fully functioning, 5,000 tons of biodiesel a year will be produced, enough to power a bus for 62 million kilometres; or 8 to 10 trips around the world.

�